Manually setting up a data processing system is time consuming work. For instance, it may take hours to install and configure the operating system (OS), drivers, and user applications desired for a particular personal computer (PC).
In certain situations, automation may be used to expedite the process. For instance, if many processing systems with identical hardware are to receive identical software components and configurations, one system to serve as a model may be manually loaded with the desired software and configured. A disk image from the model system may then be copied to each of the other systems, to provision those systems with the same software and configuration as the model system. The processing systems to be provisioned may be referred to as managed systems or managed platforms. The model image may be stored on a processing system operating as a server. Each managed system may also include firmware that runs in a preboot execution environment (PXE), retrieves the model image from the server, and loads the model image into a local hard disk drive. The managed system may then launch an OS from the local hard disk drive.
However, such a model disk image may easily exceed ten gigabytes (GB). Consequently, even though it may be unnecessary to manually install and configure individual software components, a significant amount of time is nevertheless required to provision a system from a model disk image.
Once the model image has been loaded, that image may be modified by subsequent use of the managed system. For instance, a user may intentionally or inadvertently modify the configuration settings, install new software, cause the system to receive a virus, or otherwise alter the original image. Such modifications may adversely effect how the processing system functions for subsequent users, or otherwise cause undesirable results.
Two types of adapter cards, known as hard drive (HD) protection cards or HD recovery cards, have been designed to protect the data on a hard disk drive from modification. The first type of HD protection card divides a hard disk drive into a visible partition and a hidden partition. The HD protection card then intercepts every IDE write command directed to the visible partition, and redirects those writes to the hidden partition. Subsequent reads involving the data written to the hidden partition are then also redirected to the hidden partition. Alternatively, the HD protection card can allow the write commands to modify the data in the visible partition, but only after copying the original data from the visible partition to the hidden partition.
After an HD recovery card has processed write transactions as indicated above, the user may decide whether or not to accept the modifications permanently. Alternatively, the HD recovery card may accept policy settings that cause the processing system to revert to the original data whenever the system is rebooted. For example, if writes were redirected to the hidden partition, the HD recovery card may discard or disregard the data in the hidden partition after the reboot. If writes were applied to the original partition after copying the original data to the hidden partition, the HD recovery card may copy the original data from the hidden partition back to the visible partition.
A Chinese company known as Nanjing HardSoft advertises the second type of HD protection card. Like the first type of card, the second type also uses space on the hard drive to store both the original data and the modified data. However, the second type of card may not require the use of a hidden partition on that disk drive. Instead, the second type of card may simply utilize unused blocks in the visible partition.
Both types of cards may track the changes in a modification log. The modification log may be stored in the hard drive itself, or possibly in flash memory or some other type of storage onboard the HD protection card.
Both types of HD protection cards may reduce the runtime performance of the processing system by approximately 20%. For instance, system performance is reduced significantly when original data is copied to a second location on the hard disk before a write is allowed to modify the data in the first location, and when reads and writes are redirected. In addition, since space on the hard drive is required for the original data and the modified data, the hard disk capacity available to the user may be reduced to approximately 50% of the actual capacity of the hard disk.